\begin{figure}[ht] \begin{tabular}{cc} \begin{minipage}[t]{0.4\hsize} \centering \begin{equation*} \frac{\Gamma, x:\tau_a \vdash e:\tau_b}{\Gamma \vdash \lambda x.e:\tau_a \to \tau_b } \end{equation*}\textrm{T-LAMBDA} \end{minipage} & \begin{minipage}[t]{0.5\hsize} \centering \begin{equation*} \frac{ \Gamma \vdash e_1:N \quad \Gamma \vdash e_2:\tau }{\Gamma \vdash delay\ e_1\ e_2 : \tau} \end{equation*}\textrm{T-DELAY} \end{minipage}\\ \begin{minipage}[t]{0.4\hsize} \centering \begin{equation*} \frac{\Gamma, x : \tau_p \vdash e: \tau_p }{\Gamma \vdash feed\ x.e:\tau_p} \end{equation*}\textrm{T-FEED} \end{minipage}& \begin{minipage}[t]{0.5\hsize} \centering \begin{equation*} \frac{ \Gamma \vdash e_c : R\ \Gamma \vdash e_t:\tau\ \Gamma \vdash e_e:\tau }{\Gamma \vdash if\ (e_c)\ e_t\ e_e\ : \tau} \end{equation*}\textrm{T-IF} \end{minipage}\\ \end{tabular} \caption{\label{fig:typing}{\it Excerpt of the typing rules for \lambdammm.}} \end{figure}